The volume represents the proceedings of the 9th International Workshop on "Polymer Reaction Engineering" held at the University of Hamburg, Germany, in cooperation with DECHEMA. For more than twenty years the workshop series and the corresponding proceedings successfully accompany the chemical community promoting the update, exchange and discussion of new findings in the field of polymer reaction engineering between experts from academia and industry alike. This new title covers in detail topics ranging from new catalysts, high-throughput methods to process analytics, micro technologies, green processes and much more.